Scott Thompson says players who go into a game sore open themselves up to being targeted by the opposition.

The All-Australian defender admitted he wore a guard to protect a broken rib against the Cats, evidence that proved the resounding factor in Steve Johnson being cleared to play this week.

While Thompson was keen to hide his pain on Saturday night, his approach won't be affected with the injury now public knowledge.

"I wasn't concerned going into the game last week either," he told The Canberra Times.

"I'm not worried, if someone goes into the game with something sore you expect them to know about it and target it. If it happens during a game [and you're trying to get off] it's a bit different, but if you carry it into a game it's open slather."

Thompson is expected to go into the clash against GWS minus the guard, and he'll need to be 100 per cent against twin towers Jonathon Patton and Tom Boyd.

"It doesn't matter about their experience, Patton and Boyd have definitely got the ability of turning a game off their own boot," he added.

"You've got to treat them with respect and they're great players already. You've got to do your homework and make sure you're ready to play on them."